Yesterday morning, Matthew Whitaker was chief of staff to the attorney general of the United States. Today he is the acting attorney general. President Trump fired Jeff Sessions and ordered Whitaker to take over. Whitaker has experience. He's a former U.S. attorney. He also has a political background and talked in the past on TV about ways to end the investigation into Russian interference in the 2016 election, an investigation he now oversees. We've called Democratic Senator Chris Coons of Delaware to talk about this.

Senator, welcome back to the program.

CHRIS COONS: Thanks, Steve. Great to be on with you again.

INSKEEP: Thank you. You ever met Matthew Whitaker?

COONS: I have not.

INSKEEP: What do you know about him?

COONS: What I know is that he's the former U.S. attorney for the state of Iowa. He had a job literally criticizing the Mueller investigation and making comments about different legal matters for a nonprofit before he was brought into the Trump administration. As you mentioned, just a year ago in public interviews on CNN, he was hypothesizing about how the president might fire the attorney general, avoid the succession process within the Department of Justice - which would have led Rod Rosenstein to be the acting attorney general - appoint someone political like Matt Whitaker, and then that person who now controls the budget of the special counsel could gradually squeeze or close or shut down Bob Mueller's investigation.

INSKEEP: I guess we should note that we do not know that that is Whitaker's intent now that he really has the job, but you are correctly saying what he did say. What do you assume the president's objective would be in firing Jeff Sessions right now?

COONS: Well, the president has long said that he was deeply angry at Jeff Sessions - Sessions, who was his first and strongest supporter in the Senate - for recusing himself from the ongoing investigation by Robert Mueller. He made no mystery of the fact that he wanted him gone as soon as possible. The only reason he delayed until after the midterm elections was opposition from Republican senators.

INSKEEP: Well, that raises another issue here, Senator Coons, because several Republican senators have commented since this change was made. And at least three that I can think of specifically have warned the president - Lamar Alexander, Susan Collins, Mitt Romney, who's a senator-elect now - saying that no successor can be confirmed as attorney general unless that person supports Robert Mueller's investigation into Russian interference. Do you believe that, that Republicans are not going to let someone come in whose job is to destroy that investigation?

COONS: Well, I found those public statements by those three senators encouraging, but the most important senator here is Mitch McConnell, the majority leader of the Senate. He could bring to the floor as early as Tuesday for a vote the bipartisan bill that has already cleared the judiciary committee that I wrote, along with Senators Graham and Tillis and Booker, that would protect the special counsel from firing. It would put in statute what is currently in regulation, which is a prevention from the firing of the special counsel for anything other than good cause.

There's other steps we can and should take. If those senators want to join with others of us in demanding that Whitaker come before the judiciary committee during his tenure as the acting attorney general and confirm what he's doing in terms of oversight of the special counsel investigation, that'd be a constructive step, too. We could be doing that as early as Monday.

INSKEEP: I believe you just said that you co-authored that legislation with Lindsey Graham, who's been a very vocal supporter of the president the last year or so.

COONS: Correct. It's my hope that Senator Graham will continue to support the legislation that we both worked so hard on over the last year.

INSKEEP: For the moment, though, you have this acting attorney general who it sounds like you have questions about his motives. Is there anything Democrats can do in the next month, two months, five months, whatever it is, to restrain him?

COONS: We can't restrain him effectively without Republicans partnering with us because we're in the minority in the Senate. But I'm encouraged by the conversations I had last night and by some of the public statements that have been made by Republican colleagues and friends of mine.

INSKEEP: You do not believe there is any way to end this investigation without a crisis?

COONS: Correct. Robert Mueller has to complete this investigation to its logical conclusions. That is in the best interest of the rule of law. It's in the best interest of the president. If he's innocent, he should start acting like it and stop trying to interfere with Robert Mueller's investigation.